Non-Transient Non-Community Water System · PWS SD4680046
Nps-Mount Rushmore National Memorial
Operator location Keystone, South Dakota - 93% of 68 violations are health-based (upper-third health share (> 23%)); groundwater source; 4,100 served per SDWIS.
- 4,100
- People served (this PWS)
- 68
- EPA violations (this PWS)
- 63
- Health-based (this PWS)
- 3 PFAS
- UCMR5 (this PWS)
Nps-Mount Rushmore National Memorial standing, mid SDWIS violation third
93% of 68 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 93% is upper-third health share (> 23%). UCMR5: middle-third PFAS panel (≤ 4 compounds). Population rank #8,727 of 29,740 among systems serving 500+.
The verdict
Nps-Mount Rushmore National Memorial lands in the middle third by violation volume (68), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is large (4,100; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 93% - most of this ledger is MCL or treatment-technique exceedance. UCMR5 detected 3 PFAS compounds (middle-third PFAS panel (≤ 4 compounds)).
- #8,727 of 29,740
- Population · /systems
- #38 of 171
- Population · SD
- 68
- Total EPA violations on record
- 93%
- Health-based (MCL / treatment failure)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
3 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
System Details
- System Type
- Non-Transient Non-Community
- Owner Type
- Federal
- Connections
- 19
- County
- Pennington
- School/Daycare
- No
- MCL Violations
- 63
- Monitoring Violations
- 5
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Arsenic | MCL | 63 | 2011 |
| Revised Total Coliform Rule | MON | 3 | 2022 |
| Coliform (TCR) | MR | 2 | 2010 |
Violation Count vs. the National Corpus
Nps-Mount Rushmore National Memorial has 68 recorded EPA violations, 64% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 35% carry more. 93% of this system's own violations are health-based (63 of 68), and it ranks #8,727 of 29,740 by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
68 Around the middle fewer violations than 35% of 29,740 water systems
the national water-system corpus, bucketed by value
Each bar is a band; taller bars hold more water systems. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA SDWIS · 2026-05-15
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 5 of 58 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| NMeFOSAA | 6/14/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| 8:2 FTS | 6/14/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBS | 6/14/2023 | 3.20 ppt | 3.00 ppt | Detected |
| PFHpA | 6/14/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 6/14/2023 | 20.80 ppt | 3.00 ppt | Detected |
| NEtFOSAA | 6/14/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTA | 6/14/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFNA | 6/14/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 6/14/2023 | 9.80 ppt | 4.00 ppt | Detected |
| PFOA | 6/14/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDA | 6/14/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 6/14/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| ADONA | 6/14/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 6/14/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 6/14/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 6/14/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFPeS | 6/14/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 6/14/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 6/14/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 6/14/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 6/14/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHpS | 6/14/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 4:2 FTS | 6/14/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 6/14/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFEESA | 6/14/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 6/14/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 6/14/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 6/14/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDoA | 6/14/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 3/18/2024 | 10.50 ppt | 3.00 ppt | Detected |
| PFOS | 3/18/2024 | 10.60 ppt | 4.00 ppt | Detected |
| PFTrDA | 11/7/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| 4:2 FTS | 11/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 11/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 11/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOA | 11/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDA | 11/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 11/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 11/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 11/7/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 11/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 9Cl-PF3ONS | 11/7/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| ADONA | 11/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 11/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 11/7/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| 6:2 FTS | 11/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NEtFOSAA | 11/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 8:2 FTS | 11/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 11/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeA | 11/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
Health-based violations on Nps-Mount Rushmore National Memorial
63 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for SD4680046.
Sources: EPA SDWIS
Nationwide peers
68 violations · 4,100 served: nearest cross-state SDWIS matches.
Cross-state systems near this violation count
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
Cross-state systems with similar served population
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Nps-Mount Rushmore National Memorial
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in South Dakota compares on the same EPA violation measures. South Dakota systems
- Check whether PFAS was detected at this system under UCMR5 testing. PFAS guide
- Find and compare another public water system by name or PWSID. Search systems
EPA SDWIS and UCMR5 figures are informational only, not a substitute for a certified lab test of your own tap water.